Hospital bed

ABSTRACT

A hospital bed for patients who require assistance in repositioning themselves on the bed. A mattress for the bed is formed by a number of separate bolsters or cushions each covered with a removable slip-cover sheet. Each bolster extends across the width of the bed, and the several bolsters are aligned side by side to extend along the length of the bed. A drive mechanism is provided on a frame of the bed to move the bolsters as a group along the length of the bed, thereby enabling longitudinal repositioning of the patient. End portions of the bolsters can also be raised to assist it turning the patient. In an alternative form, the modular mattress is carried on a frame adapted for mounting on a standard hospital bed.

[ June 3, 1975 HOSPITAL BED [75] Inventor: Charles Hunter Shelden, San

Marino, Calif.

[73] Assignee: Huntington institute of Applied Medical Research,Pasadena, Calif.

[22] Filed: July 11, 1973 [21] AppI. No.: 383,298

Related U.S. Application Data [63] Continuation-in-part of Ser. No.171,702, Aug. 13,

1971, abandoned.

[52] U.S. Cl 5/81 R; 5/61; 5/91 [51] Int. Cl. A6lg 7/02; A61g 7/10 [58]Field of Search 297/283, 223; 5/17, 18, 5/60, 61, 63, 66, 68, 81, 90,91, 317, 88

[56] References Cited UNITED STATES PATENTS 3,623,170 11/1971 Staley eta1. 5/90 3,760.435 9/1973 .lardine 5/81 R FQREIGN PATENTS ORAPPLICATIONS 716,981 1/1942 Germany 5/8! B Primary ExaminerCasmir A.Nunberg Attorney, Agent, or FirmChristie, Parker & Hale [57] ABSTRACT Ahospital bed for patients who require assistance in repositioningthemselves on the bed. A mattress for the bed is formed by a number ofseparate bolsters or cushions each covered with a removable slip-coversheet. Each bolster extends across the width of the bed, and the severalbolsters are aligned side by side to extend along the length of the bed.A drive mechanism is provided on a frame of the bed to move the bolstersas a group along the length of the bed, thereby enabling 1ongitudinalrepositioning of the patient. End portions of the bo1sters can also beraised to assist it turning the patient. In an alternative form, themodular mattress is carried on a frame adapted for mounting on astandard hospital bed.

16 Ciaims, 19 Drawing Figures PATENTEDJUH3 1915 3.886510. SHEET 2HOSPITAL BED CROSS REFERENCE TO RELATED APPLICATION This is acontinuation-in-part of my co-pending patent application Ser. No.171.702 titled Hospital Bed and filed Aug. 13, 1971, now abandoned.

BACKGROUND OF THE INVENTION Many modern hospitals haveintensive-care-unit (ICU) facilities where post-operative, criticallyill or unconscious patients can be kept under constant surveillance bynurses. It is normally preferred that the upper part of the patientsbody be elevated for easier breathing and other medical reasons, and ICUbeds are therefore usually of a conventional type having a head sectionwhich can be cranked up to raise the patient's head and shoulders. Anunfortunate by-product of this preferred elevated position is that thepatient gradually slides downwardly toward the foot or toe end of thebed, and must be frequently repositioned by a nurse or orderly. Thepatient must also be moved to use a bed pan, or when bed linen is to bechanged.

The problem of moving a bed patient is serious in ICU facilities as mostICU patients are either comatose or unable to exert sufficient muscularcontrol to move themselves. These seriously ill patients are awkward tomove, not only because of normal body weight, but also because greatcare must be taken not to interfere with intravenous feeding tubes,drainage tubes, EKG cables, and similar equipment attached to thepatients.

ICU nurses are constantly faced with the problem of overexertingthemselves in repositioning patients who may weighseveral hundred poundsor more, and back strain is a common complaint from these nurses. ICUsurveillance should be maintained by highly skilled and experiencednurses in view of the serious condition of ICU patients, but hospitaladministrators find that the best-qualified nurses shy away from theseduties because of the muscle strain and back problems arising from thephysical exertion required to reposition patients in their bed.

.The bed here disclosed solves these problems as it provides mechanicalassistance for shifting, raising or turning a bed patient. A mattressassembly for the bed is formed by a number of bolsters or cushions whichextend across the width of the bed, the bolsters being positioned sideby side so the resulting assembly extends from the head to the foot ofthe bed. A motor-driven drive belt extends along the length of the bed,and the bolsters are connected to the belt. If the patient is to bemoved toward the head end of the bed, the drive-belt motor is actuatedto move the belt and bolsters mounted thereon in the desired direction.As an end bolster moves past the head end of the bed, it is lifted offthe belt and replaced at a starting position on the belt at the bedfoot.

An ICU nurse is thus able to reposition a heavy patient by simplypushing a button to actuate the beltdrive mechanism. Alternatively, thedrive motor may be omitted, and a simple hand-crank drive is used todrive the bolsters along the bed. This moving modular arrangement can bemade as a complete bed, or as an add-on accessory for installation onexisting bed frames.

The bolsters are light and easily repositioned by the nurse, and arecovered by a slip-cover sheet which is quickly replaced when fresh linenis needed. Any bolster in the series comprising the mattress can beindividually removed for a linen change, or to provide a clear spacebeneath the patient for a bed pan, or for improved air circulation overor access to a body area being treated. One end of the bolsters can alsobe raised to assist in turning the patient on his side.

SUMMARY OF THE INVENTION This invention relates to a hospital bed havinga frame with head and foot ends, the head end being elevatable to raisean upper part of the patients body. A mattress is supported on theframe, and a drive means on the frame is engageable with the mattress tomove the mattress longitudinally along the frame and upwardly along theelevated head-end portion to reposition the patient on the bed.Preferably, the mattress is formed from a plurality of separate bolstersections, each of which includes a support tray and a body of resilientmaterial in the tray.

The drive means may include one or more drive belts extending betweenrollers on opposite ends of the frame, and a motor or crank drive tomove the belts. A releasable fastener means or frictional engagementcouples the belt or belts to the bolster sections, and the bolstersections are moved as a group toward an end of the frame by operatingthe motor. When a leading bolster section approaches a roller at one endof the frame, that section is removed from the belt and replaced at theopposite end of the frame. A limit switch is provided to preventinadvertent overtravel of the leading bolster. The bed may also includea power-operated lifting means to raise one end of a selected bolstersection, or to tilt or raise the entire bolster section to aid inrepositioning the patient.

In one form the invention is incorporated in an accessory system havinga frame adapted for attachment to a standard hospital bed, permittingconversion of existing equipment for ICU use. Also disclosed is abed-pan module which can be temporarily substituted for one of themattress bolsters.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I. is a side elevation of ahospital bed according to the invention;

FIG. 2 is a top view of the bed;

FIG. 3 is a view on line 33 of FIG. 1;

FIG. 4 is a view on line 4-4 of FIG. 3;

FIG. 5 is a schematic diagram of a belt-drive system used in the bed;

FIG. 6 is a schematic diagram of the bed electricalwiring system;

FIGS. 7-9 are schematic diagrams showing a sequence of events as the bedis operated;

FIG. 10 is a plan view of a modified mattress-bolster carrier usefulwith the invention;

FIG. 11 is a side elevation of the carrier taken on lines 1111 of FIG.10'. FIG. 12 is an end view of a portion of the bed showing theoperation of the modified mattress-bolster carrier.

FIG. 13 is a side elevation of a conventional hospital bed and anaccessory movable-mattress system;

FIG. 14 is a top view of the accessory system;

FIG. 15 is a view on line 1515 of FIG. 13:

FIG. 16 is a schematic diagram of a belt-driven system used in theaccessory system.

FIG. 17 is a front elevation of a bed-pan unit:

FIG. 18 is a side view of the bed-pan unit; and FIG. 19 is a top view ofthe bed-pan unit.

DESCRIPTION OF THE PREFERRED EMBODIMENT A hospital bed according to theinvention is shown in FIGS. 1 and 2, and the bed includes a com entionalmain frame 11 with longitudinal and lateral frame members 12 and 13respectively. Conventional tubular legs 14 are mounted at the fourcorners of the main frame. and carry caster wheels 15 at their lowerends.

An upper mattress-supporting frame 18 is mounted above main frame 11 ona pair of upright brackets 19 secured to the central part of eachlongitudinal frame member 12. The upper frame includes a pair of firstrails 20 pivotally secured to brackets 19 to permit the head end of theupper frame to be elevated to raise the upper part of the patients body.A pair of second rails 22 extend from brackets 19 toward the foot of thebed, and these rails may also be pivotally secured to the brackets if itis desired to elevate the lower part of the patients body. Cross braces(not shown) extend between the pairs of rails to form a rigid structure.The details of this construction are omitted from the drawings as thisstyle of framework (and the mechanism for raising the frame sections) isconventional in hospital beds.

A pair of main rollers 25 are mounted on opposite ends of the upperframe, and each roller is rotatably supported by a pair of bearings 26secured to the upper frame. A plurality of continuous drive belts 27extend between main rollers 25 along the length of the upper frame. Theundersurface of the upper part of each belt loop is supported by aplurality of rigid metal panels 28 which are secured to and extendbetween the upper surfaces of rail pairs 20 and 22.

A guide means including a set of three hold-down rollers 31 guides belts27 past the pivotal connection of first rails 20 to brackets 19. Two ofthe rollers are rotatably mounted in bearings (not shown) secured tofirst rails 20, and the third roller is similarly mounted to brackets19. A lower guide roller 32 (FIG. 5 is also rotatably mounted onbrackets 19, and provides guidance for the lower part of the drive-beltloops.

A main drive roller 34 extends between first rails 20, and is rotatablysupported in bearings 35 secured to the first rails. A tension roller 36is rotatably mounted on a pair of arms 37 which are pivotally connectedto first rails 20. A variable-length element 38 such as a turnbuckle orspring is connected between the lower end of each arm 37 and the frame,and element 38 is adjusted to remove any slack from the belts. Theoverall arrangement of the belts and various rollers is shown inschematic form in FIG. 5.

A drive motor 41 which includes a speed reducer is secured to the upperframe on one of first rails 20 and associated cross braces. Thisdrive-motor speedreducer assembly is of a conventional type having anoutput shaft (not shown) connected to main drive roller 34 by a chain orbelt 42. These components are covered by sheet-metal shields which areomitted in the drawings for clarity.

An electrical wiring diagram for drive motor 41 is shown in FIG. 6. Oneterminal of a pair of power-input terminals 45 is connected to a commonterminal 46 on the motor. The other power-input terminal is connectedthrough a pair of limit switches 47 and 48 (described below) to the armof an SPDT operate switch 49. The fixed contacts of the operate switchare connected to a forward terminal 50 and a reverse terminal 51respectively of the drive motor. With limit switches 47 and 48 in theirnormally closed positions. the operate switch (which may be mounted atany convenient location on the bed) is actuated to drive the motor ineither a forward direction (moving the upper surface of the drive beltstoward the head end of the bed) or a reverse direction.

A mattress 53 for the bed is formed from a plurality of mattresssections or bolsters 54 which are elongated rectangular-cross-sectionblocks of a resilient material such as foam rubber. Each bolster iscovered by a slipcover sheet made ofa material such as cotton cloth.Alternatively. the slipcover may be made of sheepskin or a syntheticdecubituspad material. A metal tray 55 with upturned edges receives eachbolster 54 and serves to couple the bolsters to belts 27.

The outer surface of each drive belt 27 includes a body of pile fastenermaterial 57 such as sold under the trademark Velcro." Mating strips ofhook material 58 of this type are secured to the undersurface of eachtray 55 as best seen in FIG. 3. The tray and associated bolster are thusconnected to the drive-belt system simply by pressing the tray againstthe belts to engage the hook and pile sections of this fastenermaterial. Other types offastening means can of course be used to connectthe trays to the drive belts.

Limit switch 47 is mounted on the undersurface of one of metal panels 28adjacent the foot end of the bed (FIGS. 3 and 4). This switch has anupwardly extending roller-carrying arm 60 which is urged upwardlythrough an opening 61 in the panel. If a bolster is present above theswitch, arm 60 is depressed by associated tray 55 to close the switch.If no bolster is present above the switch, the switch arm moves upwardlyto a position which opens the switch contacts and prevents operation ofdrive motor 41. Limit switch 48 is similarly arranged at the head end ofthe bed, but his switch is of a normally closed type. That is, thecontacts of switch 48 open to disable drive motor 41 only when a bolsterand associated tray move over the switch to depress the switch arm.

Operation of the bed is shown in schematic form in FIGS. 7-9. In FIG. 7,upper frame 18 has been loaded with eight mattress bolsters 54designated a-h, and associated trays. If a patient resting on themattress slides downwardly toward the foot end of the bed, drive motor41 is actuated by switch 49 to drive the bolsters in a forward direction(toward the head of the bed) to move the patient back to a desiredposition. This transport of the mattress sections can be continued untilthe bolsters reach the position shown in FIG. 8 where the limit switchesopen to disable the drive motor and thus to prevent overtravel of thebolsters. Bolster /i at the head end of the bed is then removed bypulling its associated tray away from the drive belts, and this bolsteris replaced in the now-vacant space at the foot of the bed as shown inFIG. 9. The patient can thus be moved upwardly in the bed simply byactuating the drive switch, and periodically moving the leading bolsterback to the foot end of the bed.

A continuous mattress can also be used to eliminate manual transfer ofindividual bolster elements. but the bolster construction is preferredfor its mechanical simplicity. and also because soiled bolster coverscan be individually replaced without changing all of the bed linen.Another advantage of the bolster construction is that a single bolstercan be removed from beneath the patient's hips to permit use of a bedpan, or to provide access to the underside of the patients body. Theindividual bolsters are light and easy to handle for a nurse, andreplacement of a bolster cover is readily accomplished.

Another advantage of the individual bolsters is made possible by amodified bolster tray 65 (FIGS. -11). This tray is generally similar inshape to tray 55 in that it has a flat base panel 66 with upwardlyturned edges 67 to receive a bolster 54. Tray 65, however, includes apair of movable panels 68 pivotally mounted by hinges 69 on oppositesides of the tray centerline. An opening 70 is formed through each endof base panel 66.

A pair of lifting meanssuch as electrically operated jackscrews 72 (FIG.12) with drive motors 73 are used in connection with tray 65, and thedrive motors are secured by brackets 74 to the rails of upper frame 18.For example, one pair of jackscrews can be mounted to rails spacedslightly from rails 22 toward the head end of the bed. and another pairofjackscrews can be mounted on rails 22 slightly toward the foot of thebed from rails 20. A pad 75 is mounted by a ball-socket fitting at thetop end of each jackscrew.

If it is necessary to turn the patient in the bed, the jackscrews on oneside of the bed are actuated to raise one end of the associated bolstersas shown in FIG. 12. The patient is turned as the bolster ends areelevated, and manual effort required to reposition the patient isconsiderably reduced. When the jackscrews are used in this mode, thebolsters are positioned by drive belts 27 to place openings 70immediately above the jackscrews so pads 75 can contact hinged panels 68to raise the bolster end. 1

The jackscrews are also useful to tilt a pair of bolsters c and easshownschematically in FIG. 9. In this mode, the trays are positionedso pads 75 contact the solid undersurface of base panel 66 at one sideof opening 70. The associated bolsters are then tipped upwardly to raisethe patients hips, and thus to enable ready removal of bolster d. A bedpan can then be easily moved into position beneath the patient withoutany extra exertion on the part of either the nurse or the patient. Thetray is also readily adapted for manual operation by levers or cranks ifpower assistance in raising or turning the patient is not considerednecessary in a particular application of the bed.

An alternative form of the invention is shown in FIGS. 13-16 whichillustrates an add-on accessory movable-mattress system 90 useful forconverting a conventional hospital bed 91 to incorporate the advan-.tages of the invention. Bed 91 is of a standard style having anarticulated bed frame with an elevatable headend portion 92 and a hingedfoot-end portion 93 which can also be elevated. The usual cranks ordrive-motor mechanisms for elevating these frame portions are omitted inthe drawings.

a panel 101 which extends across the width of the section.

Retaining flanges 103 (FIGS. 13 and 15) extend downwardly from sections97-99 of frame 96 to overlap the angle-iron frame of bed portions 92 and93. These flanges anchor accessory system against sideways movement onbed 91. Flanges 103 on head section 97 include clamp screws 104 whichare tightened against the frame of bed 91 so the head section is alsolocked against longitudinal movement with respect to head-end portion92. Central and foot sections 98 and 99 are free to slide along foot-endportion 93 to accommodate changes in the frame geometry as the variousmovable portions of the bed are elevated.

A continuous and flexible drive belt 107 (which may be canvas) extendsalong the length of accessory system 90 between a drive roller 108rotatably mounted adjacent the end of head section 97 and a returnroller 109 rotatably mounted adjacent the end of foot section 99. Adrive means such as a crank handle 110 is connected to drive roller 108,and the crank handle and drive roller connection may include gearing andrachet locks (not shown) so the belt can normally be driven onlyclockwise as viewed in FIG. 13. If a rachet is used, it shouldpreferably be of a releasable type permitting reverse drive of the beltif desired.

As shown schematically in FIG. 16, a number of guide rollers 113 extendacross accessory system 90 between rollers 108 and 109 to insure propertracking of belt 107. A tensioning roller 114 is movably mounted, and isurged by a tension spring 115 into a position which keeps the drive belttaut.

A plurality of mattress bolsters 54 as described above are positionedalong the top of accessory system 90 to rest on drive belt 107. When thebelt is driven by rotating roller 108, the bolsters are driven towardthe elevated head end of the bed to reposition a patient as alreadydiscussed. There is sufficient frictional engagement between thebolsters and the wide drive belt that no special coupling is necessarybetween these components.

Preferably, the upper end of head section 97 is lengthened to form aplatform 118 to accommodate and temporarily hold the uppermost bolsteras the patient is being repositioned. An accordian-like end section 119is preferably secured at the outer end of foot section 99 to hold thebolsters at the foot end of the bed in position. End section 119 hasinternal springs 120 which are compressed to compress the end sectionwhen a bolster removed from the head end is being replaced at the footend of the movable-mattress system.

Accessory system 90 is advantageous in that it can be added to existinghospital beds to provide the patientconveyance features of theinvention. Installation and removal is straightforward, permittingconversion of standard beds for either ICU use or ordinary ward usedepending on the nature of the patient load being carried by thehospital.

FIGS. 17-19 show a bed-pan unit which is useful with either of theembodiments of the invention described above. Unit 125 is channelshaped, and is formed from two halves 126 and 127 each having a toppanel 128 and a pair of downwardly extending legs 129 along oppositeside edges of the top panel. The length and height of the abutted halvesare substantially the same as the corresponding dimensions of bolster54, and the width of the halves equals the width of the bolster or amultiple of such width. That is, the halves may, for example, span thewidth of two adjacent bolsters. An opening 130 is formed in the innerend of the top panel 128 of each half. and a raised partial seat 131extends around the opening.

In use, the patient is turned slightly so one of halves 126 and 127 canbe slipped over the bolster (or bolsters) beneath the patients buttocks.The patient is then turned slightly in the opposite direction, and theother half is similarly installed from the opposite side of the bed toabut the inner end of the first half. The assembled halves thus form acomplete seat beneath the patient, and the bolster (or bolsters) beneaththe halves can now be slipped out as the patient is supported by unit125. With the bolster thus removed, an open space is available beneathtop panels 128 and between legs 129 for insertion of a bed pan beneathopening 130.

A presently preferred arrangement for the bed pan comprises a ring 132having an outside dimension slightly smaller than that of opening 130. Apair of support arms 133 extend from opposite ends of ring 132, and theouter ends of the arms form hooks 134 which fit over the edges of toppanels 128 as shown in FIG. 17. One of the hooks is hinged to act as areleasable latch fitting over the adjacent edge of the top panel.

A conventional solid bowl-shaped bed pan (not shown) can be fitted intoring 132, but preferably a disposable transparent plastic bag 135 issecured around the edges of the ring to extend downwardly through thering as shown in FIG. 18. The bag preferably has a selfadhesive lip topermit quick and simple fastening in place. After the bag is installed,the ring is slipped into the open space beneath top panels 128, andhooks 134 are engaged with the top panel edges to raise ring 132 and theupper end of bag 135 into opening 130 beneath the patients buttocks.

After use, the bed-pan unit is slipped out from beneath top panels 128,the bag is removed from ring 132 and sealed, and the bag contents may beweighed or checked for appearance as is often required with seriouslyill patients. The mattress bolster (or bolsters) is then replacedbeneath the bed pan units, and halves 126 and 127 are removed.

Bag 135 is preferably a transparent polyvinyl-alcohol plastic whichdissolves when immersed in water at a temperature of about 140F. Whenthis material is used, the bag can be discarded in a toilet which has ahot water supply, and the bag will dissolve harmlessly without blockingthe toilet plumbing.

There has been described a hospital bed system which is particularlysuited for use in intensive care units where patients are usually unableto assist themselves when repositioning on the bed is required. The bedeliminates a major part of the manual effort normally required by ICUnurses to reposition a patient, and the long standing problems offatigue and back strain often encountered by these nurses is solved.

What is claimed is:

1. A bed, comprising:

a bed frame having a foot end and a head end. the frame being hinged sothe head end can be raised to elevate a patients upper body;

mattress means for supporting a patient on the bed frame;

drive means on the frame and engaged with the mattress means for movingthe mattress means longitudinally toward the head end of the bed andalong an upwardly sloping portion of the frame adjacent the head endwhen the head end is elevated,

whereby a patient who has slipped downwardly toward the foot end can bemoved back toward the head end and along the upwardly sloping frameportion by moving the mattress means.

2. The bed defined in claim 1 in which the drive means includes rollersrotatably mounted at the head and foot ends of the frame, a drive beltextending between the rollers in engagement with the mattress, and meanscoupled to the drive belt for maintaining the belt under tension as theelevation of the head end is adjusted.

l5 3. A bed, comprising:

a bed frame having head and foot ends, the frame being arranged so anupper frame portion adjacent the head end can be sloped upwardly withrespect to a lower frame portion adjacent the foot end,

whereby an upper portion of a patients body can be elevated; mattressmeans on the frame and including a plurality of separate bolstersections each extending laterally across the frame, the sections beingpositioned side by side to extend between the ends of the frame; and

drive means on the frame and engageable with the bolster sections formoving the sections along the frame toward the head end and along theupper frame portion whereby a patient who has slipped downwardly in thebed can be moved back toward the head end and along the upwardly slopingframe portion without being raised off thebolster sections.

4. The bed defined in claim 3 in which the drive means includes rollersmounted at the head and foot ends of the frame, a drive belt extendingaround the rollers longitudinally along the bed, the bolster sectionsbeing disposed on the belt, a guide means on the frame intermediate therollers for guiding the belt along an upper surface of the frame, meanscoupled to the belt for maintaining the belt under tension when theelevation of the upper frame portion is adjusted, and means coupled tothe belt to move the belt longitudinally along the bed. 1

5. The bed defined in claim 4 in which the bolster sections each includea body of resilient material and a support tray fitted against anundersurface of the resilient material; the drive belt and trays havinga releasable fastening means therebetween so an individual bolstersection can be removed from the belt as it reaches an end of the frameto be repositioned on the belt at the other end of the frame.

6. The bed defined in claim 5 in which said means for moving the beltincludes an electric motor, means connecting the motor to the belt, andan operate switch and a limit switch in series connection with themotor, the limit switch being mounted on the frame for actuation by thebolster sections, the limit switch being operative to disable operationof the motor when a bolster section is to be repositioned on the frame.

7. The bed defined in claim 6 and further comprising a pair of liftingmeans secured at opposite sides of the frame and arranged to lift aselected end of the body of resilient material positioned above thelifting means to aid in turning a patient.

8. The bed defined in claim 7 in which each support tray comprises abase panel with an opening at each end, and a pair of movable panelspivotably mounted on the base panel above the respective openings. anindividual tray being positionable so the lifting means can extendupwardly through the openings to raise a selected one of the movablepanels to raise the selected end of the body of resilient material, thetray further being positionable in a second position so the liftingmeans contacts the base panel to raise the entire bolster section withrespect to an adjacent bolster section.

9. The bed defined in claim 3 and further comprising lifting means onthe frame for elevating at least a portion of a selected bolster sectionwith respect to the frame.

10. The bed defined in claim 3 and further comprising a bed-pan unitadapted to be substituted for one of the bolster sections, the unithaving a top panel with an opening therethrough to receive a container.

11. The bed defined in claim 10 wherein the container is a plastic bag.

12. The bed defined in claim 11 wherein the plastic bag is formed ofpolyvinyl-alcohol plastic which is soluble in hot water.

13. An accessory movable-mattress system for addition to and use with aconventional hospital bed, the conventional bed having a bed frame witha head end which can be raised to elevate a patients upper body, theaccessory system comprising:

an elongated hinged frame adapted to fit on the bed frame, the hingedframe having a head section which can be raised in conjunction with thebedframe head end;

mattress means for supporting a patient on the hinged frame; and

drive means on the hinged frame and engaged with the mattress means formoving the mattress means longitudinally toward the head end of the bedand along an upwardly sloping portion of the frame head section when thehead section is elevated, whereby a patient who has slipped downwardlytoward a foot end of the bed can be moved back toward the head end andalong the upwardly sloping frame portion by moving the mattress means.

14. The accessory system defined in claim 13 wherein the mattress meanscomprises a plurality of separate bolster sections each extendinglaterally across the hinged frame. the bolster sections being p0-sitioned side by side to extend longitudinally along the hinged frame.

15. The accessory system defined in claim 14 wherein the drive meansincludes rollers mounted adjacent opposite ends of the hinged frame, adrive belt around the rollers longitudinally along the hinged frame, thebolster sections being disposed on and being movable with the belt, andmeans for driving the belt longitudinally along the bed.

16. The accessory system defined in claim 14 and further comprisingattachment means for securing a portion of the hinged frame to the bedframe, tensioning means coupled to the drive belt for maintaining thebelt under tension as the elevation of the head section is adjusted, andguide means on the hinged frame for guiding the belt along an uppersurface of the hinged frame. =l l =l =l

1. A bed, comprising: a bed frame having a foot end and a head end, theframe being hinged so the head end can be raised to elevate a patient''supper body; mattress means for supporting a patient on the bed frame;drive means on the frame and engaged with the mattress means for movingthe mattress means longitudinally toward the head end of the bed andalong an upwardly sloping portion of the frame adjacent the head endwhen the head end is elevated, whereby a patient who has slippeddownwardly toward the foot end can be moved back toward the head end andalong the upwardly sloping frame portion by moving the mattressmeans.
 1. A bed, comprising: a bed frame having a foot end and a headend, the frame being hinged so the head end can be raised to elevate apatient''s upper body; mattress means for supporting a patient on thebed frame; drive means on the frame and engaged with the mattress meansfor moving the mattress means longitudinally toward the head end of thebed and along an upwardly sloping portion of the frame adjacent the headend when the head end is elevated, whereby a patient who has slippeddownwardly toward the foot end can be moved back toward the head end andalong the upwardly sloping frame portion by moving the mattress means.2. The bed defined in claim 1 in which the drive means includes rollersrotatably mounted at the head and foot ends of the frame, a drive beltextending between the rollers in engagement with the mattress, and meanscoupled to the drive belt for maintaining the belt under tension as theelevation of the head end is adjusted.
 3. A bed, comprising: a bed framehaving head and foot ends, the frame being arranged so an upper frameportion adjacent the head end can be sloped upwardly with respect to alower frame portion adjacent the foot end, whereby an upper portion of apatient''s body can be elevated; mattress means on the frame andincluding a plurality of separate bolster sections each extendinglaterally across the frame, the sections being positioned side by sideto extend between the ends of the frame; and drive means on the frameand engageable with the bolster sections for moving the sections alongthe frame toward the head end and along the upper frame portion wherebya patient who has slipped downwardly in the bed can be moved back towardthe head end and along the upwardly sloping frame portion without beingraised off the bolster sections.
 4. The bed defined in claim 3 in whichthe drive means includes rollers mounted at the head and foot ends ofthe frame, a drive belt extending around the rollers longitudinallyalong the bed, the bolster sections being disposed on the belt, a guidemeans on the frame intermediate the rollers for guiding the belt alongan upper surface of the frame, means coupled to the belt for maintainingthe belt under tension when the elevation of the upper frame portion isadjusted, and means coupled to the belt to move the belt longitudinallyalong the bed.
 5. The bed defined in claim 4 in which the bolstersections each include a body of resilient material and a support trayfitted against an undersurface of the resilient material; the drive beltand trays having a releasable fastening means therebetween so anindividual bolster section can be removed from the belt as it reaches anend of the frame to be repositioned on the belt at the other end of theframe.
 6. The bed defined in claim 5 in which said means for moving thebelt includes an electric motor, means connecting the motor to the belt,and an operate switch and a limit switch in series connection with themotor, the limit switch being mounted on the frame for actuation by thebolster sectionS, the limit switch being operative to disable operationof the motor when a bolster section is to be repositioned on the frame.7. The bed defined in claim 6 and further comprising a pair of liftingmeans secured at opposite sides of the frame and arranged to lift aselected end of the body of resilient material positioned above thelifting means to aid in turning a patient.
 8. The bed defined in claim 7in which each support tray comprises a base panel with an opening ateach end, and a pair of movable panels pivotably mounted on the basepanel above the respective openings, an individual tray beingpositionable so the lifting means can extend upwardly through theopenings to raise a selected one of the movable panels to raise theselected end of the body of resilient material, the tray further beingpositionable in a second position so the lifting means contacts the basepanel to raise the entire bolster section with respect to an adjacentbolster section.
 9. The bed defined in claim 3 and further comprisinglifting means on the frame for elevating at least a portion of aselected bolster section with respect to the frame.
 10. The bed definedin claim 3 and further comprising a bed-pan unit adapted to besubstituted for one of the bolster sections, the unit having a top panelwith an opening therethrough to receive a container.
 11. The bed definedin claim 10 wherein the container is a plastic bag.
 12. The bed definedin claim 11 wherein the plastic bag is formed of polyvinyl-alcoholplastic which is soluble in hot water.
 13. An accessory movable-mattresssystem for addition to and use with a conventional hospital bed, theconventional bed having a bed frame with a head end which can be raisedto elevate a patient''s upper body, the accessory system comprising: anelongated hinged frame adapted to fit on the bed frame, the hinged framehaving a head section which can be raised in conjunction with thebed-frame head end; mattress means for supporting a patient on thehinged frame; and drive means on the hinged frame and engaged with themattress means for moving the mattress means longitudinally toward thehead end of the bed and along an upwardly sloping portion of the framehead section when the head section is elevated, whereby a patient whohas slipped downwardly toward a foot end of the bed can be moved backtoward the head end and along the upwardly sloping frame portion bymoving the mattress means.
 14. The accessory system defined in claim 13wherein the mattress means comprises a plurality of separate bolstersections each extending laterally across the hinged frame, the bolstersections being positioned side by side to extend longitudinally alongthe hinged frame.
 15. The accessory system defined in claim 14 whereinthe drive means includes rollers mounted adjacent opposite ends of thehinged frame, a drive belt around the rollers longitudinally along thehinged frame, the bolster sections being disposed on and being movablewith the belt, and means for driving the belt longitudinally along thebed.